鏈接: https://pan.baidu.com/s/1cBTTbbzRCVBCX_H4jf6qMA 提取碼: kj8w
一、實(shí)驗(yàn)原理及要求
參考textureDemo程序，實(shí)現(xiàn)太陽(yáng)、地球和月亮程序中的紋理映射，其中太陽(yáng)、地球和月亮貼上各自的紋理，同時(shí)實(shí)現(xiàn)紋理和原來(lái)光照效果的混合，即既有光照效果，又有紋理映射效果。
GLFW是一個(gè)用于OpenGL應(yīng)用程序開(kāi)發(fā)的可移植庫(kù)。它處理與OpenGL上下文創(chuàng)建、窗口管理、分辨率切換、鍵盤、鼠標(biāo)、操縱桿和時(shí)間輸入以及基本線程設(shè)施相關(guān)的系統(tǒng)特定任務(wù)。
GLEW能自動(dòng)識(shí)別當(dāng)前平臺(tái)所支持的全部OpenGL高級(jí)擴(kuò)展涵數(shù)。只要包含glew.h頭文件，就能使用gl,glu,glext,wgl,glx的全部函數(shù)。GLEW支持目前流行的各種操作系統(tǒng)
實(shí)驗(yàn)過(guò)程中，利用VAO、VBO來(lái)存儲(chǔ)直線或者圖案的點(diǎn)集vertices，然后用OpenGL的繪制功能glDrawElements將直線或者圖案繪制出來(lái)。
利用Sphere類繪制出三個(gè)球體，利用camera類實(shí)現(xiàn)視角任意轉(zhuǎn)移。
二、代碼設(shè)計(jì)和說(shuō)明

1、設(shè)置紋理映射的各類參數(shù)（環(huán)繞方式等）

定義了三個(gè)紋理變量，texture、texture2、texture3，分別獲取本地的太陽(yáng)、地球、月亮的紋理。

// 太陽(yáng)的紋理 unsigned int texture;glGenTextures(1, &texture);glBindTexture(GL_TEXTURE_2D, texture); // all upcoming GL_TEXTURE_2D operations now have effect on this texture object// set the texture wrapping parametersglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); // set texture wrapping to GL_REPEAT (default wrapping method)glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);// set texture filtering parametersglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);// The FileSystem::getPath(...) is part of the GitHub repository so we can find files on any IDE/platform; replace it with your own image path.unsigned char *data = stbi_load("sun.jpg", &width, &height, &nrChannels, 0);if (data){glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);glGenerateMipmap(GL_TEXTURE_2D);}else{std::cout << "Failed to load texture" << std::endl;}stbi_image_free(data);// 地球的紋理unsigned int texture2;glGenTextures(1, &texture2);glBindTexture(GL_TEXTURE_2D, texture2); // all upcoming GL_TEXTURE_2D operations now have effect on this texture object// set the texture wrapping parametersglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); // set texture wrapping to GL_REPEAT (default wrapping method)glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);// set texture filtering parametersglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);// load image, create texture and generate mipmaps//int width, height, nrChannels;// The FileSystem::getPath(...) is part of the GitHub repository so we can find files on any IDE/platform; replace it with your own image path.unsigned char *data2 = stbi_load("earth.jpg", &width, &height, &nrChannels, 0);if (data2){glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data2);glGenerateMipmap(GL_TEXTURE_2D);}else{std::cout << "Failed to load texture" << std::endl;}stbi_image_free(data2);// 月球的紋理unsigned int texture3;glGenTextures(1, &texture3);glBindTexture(GL_TEXTURE_2D, texture3); // all upcoming GL_TEXTURE_2D operations now have effect on this texture object// set the texture wrapping parametersglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); // set texture wrapping to GL_REPEAT (default wrapping method)glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);// set texture filtering parametersglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);// load image, create texture and generate mipmaps//int width, height, nrChannels;// The FileSystem::getPath(...) is part of the GitHub repository so we can find files on any IDE/platform; replace it with your own image path.unsigned char *data3 = stbi_load("moon.jpg", &width, &height, &nrChannels, 0);if (data){glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data3);glGenerateMipmap(GL_TEXTURE_2D);}else{std::cout << "Failed to load texture" << std::endl;}stbi_image_free(data3);

2、紋理的綁定
在每個(gè)球的glDrawElements操作結(jié)束之后，綁定紋理進(jìn)行繪制，得到三個(gè)球體對(duì)應(yīng)的紋理圖像。

3、vertex shader加入紋理坐標(biāo)屬性

//這是vertex shader#version 330 corelayout (location = 0) in vec3 aPos;layout (location = 1) in vec3 aNormal;layout (location = 2) in vec2 aTexCoord;out vec3 FragPos;out vec3 Normal;out vec2 TexCoord;uniform mat4 model;uniform mat4 view;uniform mat4 projection;void main(){FragPos = vec3(model * vec4(aPos, 1.0));Normal = mat3(transpose(inverse(model))) * aNormal;gl_Position = projection * view * vec4(FragPos, 1.0);TexCoord = vec2(aTexCoord.x, aTexCoord.y);}

4、fragment shader修改

//這是fragment shader#version 330 coreout vec4 FragColor;in vec3 Normal;in vec3 FragPos;in vec2 TexCoord;uniform vec3 lightPos;uniform vec3 lightColor;uniform vec3 viewPos;uniform vec3 objectColor;uniform sampler2D texture1;void main() {// ambientfloat ambientStrength = 0.2;vec3 ambient = ambientStrength * lightColor;// diffuse vec3 norm = normalize(Normal);vec3 lightDir = normalize(lightPos - FragPos);//入射方向float diff = max(dot(norm, lightDir), 0.0);vec3 diffuse = diff * lightColor;// specularfloat specularStrength = 0.5;vec3 viewDir = normalize(viewPos - FragPos);vec3 reflectDir = reflect(-lightDir, norm);float spec = pow(max(dot(viewDir, reflectDir), 0.0), 128);vec3 specular = specularStrength * lightColor * spec;vec3 result = (ambient + diffuse + specular) * objectColor;FragColor = texture(texture1, TexCoord)*vec4(result, 1.0); }

三、實(shí)驗(yàn)運(yùn)行結(jié)果（包含用戶輸入和輸出）
光源在相對(duì)于中心的右后方


詳細(xì)效果可參照錄屏視頻。

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